A Cable Distribution Box is one of the main products of Cotenele Electric Company. The Cable Distribution Box we produce has a small volume, compact structure, high protection level, and is sturdy and durable. A Cable Distribution Box is an electrical equipment used in power distribution networks to implement tapping, branching, splicing, and conversion circuits for cable lines. It is one of the core equipment in distribution network cabling engineering, and its main function is to distribute the electrical energy of the main cable to multiple branches, providing stable and reliable power supply for various types of electrical equipment.
The cable distribution box is widely used in urban distribution network renovation, industrial communities, residential areas, commercial centers, wind power plants, photovoltaic power generation bases and other scenarios, which can greatly save electrical equipment and cable investment and improve power supply reliability.
A Cable Distribution Box (Cable Branch Box) is a device used for tapping, branching, connecting, and converting circuits on cable lines, mostly installed outdoors.
In power systems, the Cable Distribution Box serves tapping, branching, relaying, or converting functions, connecting power cables with equipment such as compact substations, load break switches, fuse-switch combinations, and ring main units, greatly facilitating cable network construction. Cable Distribution Boxes are mainly used in power systems with a rated frequency of 50Hz/60Hz and rated voltages of 380V (660V). They are also widely used in 10kV and 35kV medium-voltage distribution networks.
The core functions of a cable branch box include:
1. Cable tapping: On a long distribution line, using multiple small cross-section cables directly would be wasteful. Therefore, a large main cable is used at the output end, and near the loads, a Cable Distribution Box divides the main cable into several small cross-section cables that connect to the loads. This connection method is widely used in street lighting power supply and small-user power supply in urban grids.
2. Cable transitioning: When the distribution distance exceeds the length of a single cable, cable joints or transition boxes are necessary. Using many intermediate joints on a long cable line can create safety hazards, so using a Cable Distribution Box for transition is safer and more reliable. In addition, The Cable Distribution Boxes facilitate the connection of cables with different cross-sections, eliminating the complex process of intermediate cable joints, improving the cable connection environment, and facilitating routine inspection and maintenance during operation.
Cable Distribution Boxes can be classified from multiple dimensions as follows.
l Ordinary distribution box: Contains no switching devices, only accessories for terminating and connecting cable ends. Simple structure, small size, single function-suitable only for tapping or branching. The total number of incoming and outgoing circuits is often called the number of branches. For example, a three-branch Cable Distribution Box can be used as one incoming with two outgoing, or two incoming with one outgoing.
l Advanced distribution box: Contains one or more switching devices, which can perform tapping, branching, as well as circuit control, conversion, and operation mode changes. Complex structure, larger size-typical external dimensions: height 1.4~1.8m, depth about 0.9~1.0m, length varies with number of switching devices. The enclosure resembles an outdoor pad-mounted transformer, with several doors- some for switch operation, others for installation and maintenance of cable connectors.
Rated voltages: 12kV (10kV), 24kV, 40.5kV (35kV), etc.
Mainly divided into three types: American-type (dead-front), European-type, and switch-equipped Cable Distribution Boxes.
| Feature | European Type | American Type | Switch-equipped Type |
| Door opening | Two-way | One-way | Depends on design |
| Connection method | Double-bushing as busbar | Horizontal multi-way busbar | Contains switching devices, allows loadoperation |
| Main circuit current | 630A | 600A | Depends on configuration |
| Branch circuit current | Depends on configuration | 200A(plug-in) | Depends on configuration |
| Connector standard | DIN47636 | IEEE 386 | Compliant with GB/IEC |
| Main features | Short length, neat cable arrangement, nolarge span crossing for three-core cables | Narrow width, flexible combination, fullyinsulated, fully sealed | Circuit control and conversion |
Outdoor floor-mounted, wall-mounted, buried type (fully insulated, fully sealed, fully enclosed -installed in cable trenches, occupying no ground space), etc.
Cable Distribution Boxes are widely used in various fields of power distribution networks:
1. Urban distribution networks: Industrial parks, residential communities, commercial centers, urban road grid upgrade projects.
2. New energy: Wind farms, photovoltaic power stations, and other renewable energy distribution access.
3. Public infrastructure: Airports, railways, switching stations, data centers, etc.
4. Large industrial enterprises: Steel, petroleum, chemical, cement, automotive manufacturing, etc.
5. Charging infrastructure: EV charging stations and other emerging loads.
6. High-speed railways: Intermediate connection and branching in railway distribution networks to ensure reliability.
7. Cableization of distribution networks: Replaces overhead lines and is a preferred product for urban and rural grid construction and upgrading.
Medium-voltage cable distribution boxes mainly including the following core components:
The core working principle of a cable distribution box is to distribute electrical energy from the incoming cable to multiple outgoing cables through internal busbar plates and cable connectors, achieving parallel distribution of power.
1. The basic wiring method: The busbar plate is fixed inside the enclosure, and cable plugs are inserted into the busbar plate. Incoming and outgoing cables connect to bushings via T-type connectors, which are then coupled together to form branching circuits. Electrical energy flows from the incoming cable, through the busbar plate (or insulating bushing/double connector) to each outgoing cable, achieving power branching.
2. European-type cable distribution boxes use insulating bushings (double connectors) as the busbar, offering advantages such as short length, neat cable arrangement, and no large span crossing for three-core cables. American-type cable distribution boxes use a horizontal multi-way busbar structure, they have the characteristics of narrow width and flexible combination. The distribution box equipped with advanced switches has a built-in switching device that divides the cable circuit into different potential incoming and outgoing sides through the opening gap, thereby achieving circuit control and conversion.
As a mature distribution network device, the cable distribution box has the following significant advantages:
1. Fully insulated, fully sealed, fully shielded structure: Ensures personal safety without additional insulation distance. The fully insulated and fully sealed structure makes the device dustproof, fire-resistant, corrosion-resistant, maintenance-free, and can be submerged in water, suitable for any harsh environment.
2. Compact size: Easy installation, simple operation, flexible combination to meet various wiring requirements, reducing footprint.
3. High protection rating: Up to IP65 or IP67, able to withstand harsh environments including high temperature, severe cold, flooding, and high dust. Also features superior moisture-proof and waterproof performance.
4. Cost savings: Greatly reduces investment in electrical equipment and cables, improves power supply reliability.
5. Low or no maintenance: Some high-end products (e.g., SF6 load break switch boxes) have a design life of up to 30 years, with the main switch requiring no maintenance.
6. Smart interface: Can be equipped with intelligent control devices, providing effective protection, remote control, and monitoring, supporting distribution automation.
Selecting the right cable distribution box is critical for safe and reliable operation. Consider multiple factors: